This invention relates to a high-speed automated chemical analyzer suited to clinical examination.
Recently, as an important clinical technique, attention has been focused on diagnosing disease through the utilization of the decomposition of enzyme components in blood. In the case of hepatic diseases, for example, the hepatic function is checked based on the measurement of enzymes released from the cells of the liver into blood, such as a gultaric/oxaloacetic acid transamylase (hereinafter referred to GOT), gultaric/pyruvic transamylase (hereinafter referred to as GPT) and .gamma.-glutamyl-transpeptidase (hereinafter referred to as .gamma.-GTP)
The IFCC has correctly recommended that the medical analyst examine not only the concentration level but also the activity level of enzymes. The activity level of the enzyme is expressed in a given unit and one unit of the enzyme is defined as an amount of enzyme required to vary 1 .mu. mol of the substrate per minute under a proper condition.
As a means for measuring the activity level of the enzyme, an ultraviolet portion reaction rate method (hereinafter referred to as a rate method) is generally known, which mixes with a blood serum a reagent containing the coenzyme nicotineamideadeninenucleoside (hereinafter referred to as NADH.sub.2) to oxidize NADH.sub.2 and time-sequentially monitors a variation in light absorption resulting from the oxidation process, whereby that activity level is evaluated.
The activity level of the enzyme in blood serum is extremely low and GOT in a healthy man is in the order of 10 to 30 IU/ml, noting that IU is an international unit. A change in absorbance of NADH.sub.2 in 340 nm corresponding to this activity level is about 0.001 to 0.003 (AbS). In order to measure the enzyme with high accuracy, a monitoring of over 1 minute will be necessary due to a smaller change in that absorbance. In this case, a discrete type one-channel automated chemical analyzer can handle only less than 60 samples per hour for checking.
In order to measure the activation level of the enzyme with high accuracy it will be necessary to confirm the linear progress of reaction, while monitoring its reaction state. It is preferred that the reaction be monitored at least for a few minutes.
Recently it is desired that in clinical examination a greater number of samples be checked for a brief period of time for the acquisition of data on a greater number of items for checking.
A large-sized automated chemical analyzer is known in the art which handles a greater number of samples over a greater number of data items on multichannel reaction lines. In this machine, however, data items to be checked are restricted for each reaction line and, moreover, it is necessary to transfer a reaction liquid from a reaction container to a cell for light measurement so that a light beam passed through the reaction liquid within the reaction container may be measured for evaluation. For a measurement to be made with high accuracy, however, a longer time is required and thus it is not possible to analytically handle samples at high speeds.
Another automated chemical analyzer is known in the art which can handle a number of data on samples in one channel. In this machine, a turntable is rotated with a number of reaction tubes arranged along a reaction line on the outer periphery thereof and, while this is done, the reaction liquid within the respective tube is directly observed. In this case, the observation of the reaction tubes is repeated, for a predetermined period of time, from the initiation to the termination of the reaction. Since only a short observation time is required for each reaction tube, it is possible to rapidly handle data items on samples, while maintaining a high measuring accuracy.
In this machine, however, it would be difficult to handle a greater number of samples in one reaction line and, for a greater amount of data items to be handled, a few sets of reaction bath blocks should be assembled for the peripheral reaction line, resulting in a bulkier machine.